COVID Vaccine, Flu Vaccine and Stroke
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https://www.cnn.com/2023/10/25/health/covid-flu-vaccine-stroke-risk-study/
Vaccines for Covid-19 and influenza may slightly increase the risk of strokes caused by blood clots in the brains of seniors, particularly when the two vaccines are given at the same time and when they are given to adults who are age 85 and older, according to a new study.
The safety signal was detected by experts at the US Food and Drug Administration who analyzed data from Medicare claims.
It is the second study to find an elevated risk of stroke for seniors after Covid-19 and flu vaccinations given together. The US Centers for Disease Control and FDA issued a public communication in January explaining that one of their near real-time vaccine safety monitoring studies — called the Vaccine Safety Datalink — had picked up a small and uncertain risk of stroke for older adults who received a dose of Pfizer’s bivalent Covid-19 vaccine and a high-dose or adjuvanted flu shot on the same day. That study triggered the FDA’s broader look at strokes after vaccination noted in the medical records of seniors on Medicare.
That said, the risk identified in the FDA’s study appears to be very small — roughly 3 strokes or transient ischemic attacks for every 100,000 doses given — and the study found it may be primarily driven by the high-dose or adjuvanted flu vaccines, which are specially designed to rev up the immune system so it mounts a stronger response to the shot.
In additional analysis of the Medicare claims data, the FDA researchers found a very slightly increased risk of stroke in adults ages 65 and older who’d only gotten a high dose flu shot. In absolute terms, the extra risk from high-dose flu shots amounted to 1-2 strokes for every 100,000 doses.
“The absolute risk is miniscule,” said Dr. Steve Nissen, a cardiologist and researcher at the Cleveland Clinic in Ohio. “I mean it is trivial in comparison to the risk for people over 85 of dying from Covid.”
